North West Bay is a relatively sheltered open estuary up to about 35 metres deep. The wide entrance, which opens at the northern end of the D’Entrecasteaux Channel, is sheltered from the open ocean by Bruny Island (Temby & Crawford, 2008).
Intertidal saltmarsh and mudflats are extensive in the northern part of the Bay and seagrass beds occur in shallow water along the western shoreline, the most common species being Tasman grasswrack (Heterozostera tasmanica) (Temby & Crawford, 2008).
A recent study (Mount & Otera, 2011) has shown that the extent of seagrass habitat in North West Bay has been in long term decline over the past 60 years. In particular, large changes were evident in the mid-1980s at Barretta and Clarkes Beach, Coningham. However, since 2008, the seagrass beds have been recolonising areas previously occupied and increasing in density.
The Bay is habitat for many fish and macroinvertebrate species. 54 macroinvertebrate species are known to occur including worms, sea snail, shrimp, sandhopper, crab and sea urchin (Temby & Crawford, 2008). The endangered Spotted handfish is also known to occur here.
The area is highly valued by the community as a place to live and play with numerous beaches (Snug Beach, Peggys Beach, Coningham Beach), parks (Dru Point Reserve, Snug, Inverawe Native Garden), boat ramps and jetties (Dru Point Boat Ramp and Margate Jetty).
Industrially, North WestBay is used for boat construction, and marine farming, as well as acting as a source to assimilate sewage, processing waste and various forms of catchment and stormwater runoff (Jordan et al.2002).
The State of the D’Entrecasteaux Channel and the lower Huon Estuary report (Parsons, 2012) states the following about North WestBay:
Continued use of North West Bay by the community and commercial users is dependent on its long-term ecological health and productivity. The D’Entrecasteaux Channel Project aims to assist in this process
Jordan, A., Doole, J., Archer, L., Lawler, M., Halley, V., and Sanderson, C., 2002, Assessment and monitoring of nutrients and habitats in North West Bay: Supporting Sustainable Management. Kingborough Council Natural Resource Management Strategy, Hobart.
Mount R. E. and K. Otera, 2011, The status of seagrass extent in North West Bay. A technical report for the Kingborough Council by the Blue Wren Group, School of Geography and Environmental Studies, University of Tasmania, Hobart, Tasmania.
Parsons, K. E. (2012). State of the D’Entrecasteaux Channel and the lower Huon Estuary 2012. Report for the D’Entrecasteaux Channel Project, Ecomarine Consulting, Tasmania.
Temby, N and Crawford, C. 2008, Coastal and Estuarine Resource Condition Assessment: A baseline survey in the Southern NRM Region, Tasmania, Tasmanian Aquaculture and Fisheries Institute, University of Tasmania, SandyBay.